[Development] Issues with QApplication::startDragDistance

[Jeremias Bosch]

Am 13.11.2014 um 12:09 schrieb Rutledge Shawn:
> Yeah we will get there eventually.  e.g. there’s just a start here
>
> https://codereview.qt-project.org/#/c/79480/
> https://codereview.qt-project.org/#/c/91242/
>
> But there are potentially a lot of these “feel” constants which should depend on the platform and on display density: the flick speed is slower than it should be, and the behavior doesn’t feel the same as in other apps on the platform.  So they need to be adjusted in the platform plugin, IMO, or in some sort of platform-specific style or theme, rather than adding new properties to Flickable and other items, because you shouldn’t need to adjust them yourself.  Correcting things that we should have already gotten right by default isn’t a good reason for cluttering up the public API, IMO.  And we actually need more of such constants rather than assuming the threshold is the same for flicking as for dragging etc.  And there are acceleration/deceleration, bounce behavior etc. which are actually hard to quantify with just a number or two.
Thanks,

I agree usually you do not want to differ from standard system behavior. 
However in my case I do. I think I need to describe the case in more 
detail so you see the picture.

I have two combined lists. One vertical, one horizontal. You can imagine 
it like a grid. One item in those lists has the size of the screen. The 
user can navigate horizontal and vertical from each item.

What I need is:

  * the user needs to move his finger about 1/3 of the screen in
    horizontal direction until his movement is recognized by the
    horizontal list as a scroll.
  * the user needs to move his finger about the 1/2 size of the screen
    in vertical direction until his movement is recognized by the
    vertical list as a scroll.

All other lists should show standard system behavior.

So a global configuration value would not work in this case, this is why 
I see the need for property on the flickable that allows us to configure 
that value per case, of course by default it should use the standard 
system value.

Best,
  Jeremias






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